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Homework Help: Acceleration across a floor with friction

  1. Jul 19, 2011 #1
    1. The problem statement, all variables and given/known data

    A man pushes a box full of toys that has a mass of 12kg across a floor with a force of 60 N. The box of toys and the floor have a kinetic coefficient of friction of 0.5.
    What is the acceleration of the box?

    2. Relevant equations

    3. The attempt at a solution

    Here's what I have so far. f[itex]\mu[/itex]k=12*9.8*0.5=58.8. So, since the man is pushing with 60 N of force, and the friction force is pushing back with 58.8 N, he is pushing the box with a net force of .2 N. I think, but I"m not sure, that I could just use this 0.2 as the F in F=ma, then solve for a, using 12 as m, and 0.2 as F. I'm not quite sure if this is correct though.
  2. jcsd
  3. Jul 19, 2011 #2
    Yes,it is correct.
  4. Jul 19, 2011 #3
    It's not 0.2 N, it's 1.2 N :)
  5. Jul 20, 2011 #4
    1.2 is the net force
    and according to newton's laws its equal to ma ...
  6. Jul 20, 2011 #5
    Always draw a free body diagram if your not sure if your correct or not. If you do so you would see that your correct.
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